マルムネミミズ

Diagnosis. Two pairs of spermathecal pores in furrows 5/6/7.  Male pores superficial at large sucker shaped porophore on segment 18.  Genital markings single, large circular sucker shape at mid-ventral line, post-setal of segments 7–8.  Simple intestinal caeca, originating in segment 27.

Material examined. Holotype (RUMF-ZO-00013): collected from litter and humus soil under the natural forest dominated by Castanopsis sieboldii, nearby Mt. Nishime-dake, Kunigami Village, Okinawa-jima Island, southwestern Japan, 26°48′12′′N, 128°16′22′′E, 350 m a.s.l., 15-II-1999, collected by Y. Azama and K. Ishizuka.  One paratype (RUMF-ZO-00014): collected from same locality as holotype, 7-XII-2014, by Y. Azama.  Three paratypes (RUMF-ZO-00015–17): same data as the holotype.

Description. Measurement and color:  Body length 60–90 mm, width 2.8–3.5 mm in segment 13.  Number of segments 91–115.  Dark-brown dorsally, light-brown ventrally, dark-brown clitellum.

External characters: Two pairs of spermathecal pores situated in furrows 5/6/7, in ventro-lateral sides, separated by a distance of ca. 1/3 body circumference.  Genital markings single, large circular sucker shape, situated on mid-ventral line, post-setal on segments 7–8, occasionally segments 6–8 in pre-clitellar, absent in post-clitellar.  First dorsal pore beginning in furrow 11/12.  Clitellum oocupying segments 14–16.  Female pore single, mid-ventrally on segment 14.  Male pore paired in segment 18, simple, superficial, separated by a distance of ca. 1/3 body circumference.  Setal number 40–54 in segment 7, 45–52 in segment 20, 8–11 between male pores.

Internal characters: Two pair spermathecae situated in segments 6–7; ampulla large and peach-shape, duct almost equal in length of ampulla; diverticulum with slender duct and oval-shaped chamber.  Genital glands situated in segment 7–8 (occasionally segments 6–8), glandular masses type, large round shape, associated with the genital markings restricted to body wall.  Septa absent in 8/9/10 thickened in 5/6–7/8 and slightly thickened in 10/11–13/14.  Seminal vesicles large, extending to the dorsal line in segments 11–12.  Intestine begins in segment 15.  Prostate glands pairs in segment 18, extending through segment 17–20, U-shaped long duct associated with male pores.  Simple intestinal caeca paired, originating in segment 27, extending anteriorly for 3–4 segments.

Etymology: The specific epithet “surculatus” in Latin word means “sucker”.  This name refers to the morphological characteristics of this species which has large circular sucker-shaped genital markings in pre-clitellar.

Remarks. The new species is distinguishable from the other congeneric species which shared morphological characteristics such as two pairs of spermathecal pores in furrows 5/6/7 and simple intestinal caeca, by single large circular sucker-shaped genital markings, at mid-ventral line post-setal on segments 7–8 (occasionally 6–8) in pre-clitellar (Chang et al., 2009; Chen, 1931, 1933, 1935, 1936, 1938, 1936; Chen et al., 1975; Gates, 1935, 1972; Ishizuka, 2001, 2015; Ishizuka and Minagoshi, 2014).